Study on the Transfer Ways of Activated Boron Atoms in the Borax Pack Boronizing Agent during Boronizing

Three different pack box techniques, which change the contacts between samples and boronizing agent, were designed to investigate how the activated boron atoms are transferred onto the sample surface during pack boronizing. It shows that the gases BF 2 and BF 3 are formed in the agent, and there are two transfer ways of activated boron atoms in the agent: gas BF 2 being absorbed and decomposed on the sample surface and activated boron atoms diffusing into sample surface directly, the later is the main transfer way. The gas BF 2 does not act as the medium of conveying boron atoms, but acts as the reductant during boronizing. The boron oxide in borax is continually reduced into activated boron atoms through circulating reaction between BF 2 and BF 3, at same time, the speed of forming activated boron atoms in the agent is also increased through the gas BF 2 absorbed and decomposed in the agent.